The present invention relates to wind devices, generally, and more particularly, to wind devices for converting wind energy into mechanical energy.
Wind devices for converting wind energy into mechanical energy are well known. Such devices employ generated mechanical energy, for example, for generating electricity, compressing air, heating water, and the like.
Known wind machines are of two basic types: (1) those having wings which rotate in a plane perpendicular to the direction of the wind, often referred to as the propeller type, and (2) those whose effective wing surfaces move in the direction of the wind, sometimes referred to as panemones. Paddlewheel rotors, cup-type rotors, open- and closed-S rotors are known examples of panemones.
Propeller type wind machines generally suffer from high initial capital and maintenance costs relative to the power each machine unit can produce. Shrouds, which include an intake section that tapers toward a throat section in which the rotor is housed, have been utilized to increase the power output of these propeller type wind machines by a factor of as much as three. Shrouds, however, have the disadvantage of being cost ineffective due to a number of factors, which include high development and manufacturing costs of three-dimensional, smoothly contoured surfaces and other intricate design features to decrease airflow separation, such as those described in Israeli Patent No. 4892812, and the large size required of these shrouds which complicates tower mounting and, also complicates the ability of the machine unit to face quickly into changing wind directions.
Panemones are usually of simple, low technological design and do not suffer, therefore, from the high initial capital costs associated with propeller type wind machines. Panemones have traditionally been mounted with their shafts perpendicular to the ground to enable them to accept winds from all directions instantly, without having to reorient themselves into the wind as wind direction changes. A major drawback associated with panemones with vertical shafts is the excessive destructive vibrations developed at high rotational velocities. This problem is compounded as the length of the rotor increases, thus substantially limiting the amount of power per machine unit.
The present invention seeks to provide a modular wind energy device for converting wind energy into mechanical energy, and which overcomes or avoids one or more of the foregoing disadvantages of the known propeller type and limitations of panemone type wind machines, and which meet the requirements of such a modular wind energy device, as more fully set forth herein.
Another object of the present invention is to provide a modular wind energy device of the panemone type which features low initial capital and maintenance costs.
Another object of the present invention is to provide a modular wind energy device of the panemone type whose modularity, i.e., easy addition or subtraction of single rotors, allows a wide power output range per machine unit.
Another object of the present invention is to provide a modular wind energy device of the panemone type having inherent stability which reduces vibration therein, compared with other known types of similar wind energy devices.
Another object of the present invention is to provide a modular wind energy device of the panemone type whose own minimal superstructure eliminates the need for a tower.
There is thus provided, in accordance with a preferred embodiment of the invention, a modular wind energy device for converting wind energy into mechanical energy, which includes:
a support structure configured for placement onto a support surface and defining an axis of rotation generally parallel thereto;
one or more panemone type rotors mounted onto the support structure for free rotation about the axis of rotation, having a pair of wing elements, of which, during rotation of the rotor in response to an airflow, at all times, one of the wing elements faces in an upstream direction and the other of the wing elements faces in a downstream direction;
a power take off element associated with the one or more rotors; and
shroud apparatus for reducing resistance against the returning wing surfaces, and for directing the airflow toward the effective wing surfaces.
Additionally in accordance with a preferred embodiment of the present invention, the one or more rotors is a plurality of rotors arranged for rotation along the rotation axis.
Further in accordance with a preferred embodiment of the present invention, the shroud apparatus includes at least a first shroud element extending forwardly of the rotors, and terminating immediately therebefore, thereby to trip a boundary layer thereat so as to provide airflow separation thereat, and thereby to provide a region of relatively still air through which the returning wing surfaces pass.
Additionally in accordance with a preferred embodiment of the present invention, there is also provided at least a second shroud element mounted onto the support structure and in association with the upstream wing element, thereby to direct the airflow towards the effective wing surface thereof.
Further in accordance with a preferred embodiment of the present invention, the second shroud element is a self adjusting element, operative to change position in accordance with the angle of incidence of the airflow.
Additionally in accordance with a preferred embodiment of the present invention, the self-adjusting shroud element has a two-dimensional airfoil profile.
Further in accordance with a preferred embodiment of the present invention, the second shroud element includes an additional forward extension, operative to increase the airflow energy directed to the effective wing surfaces of the wing elements.
Additionally in accordance with a preferred embodiment of the present invention, there is also provided additional energy collection apparatus, such as solar energy collector apparatus.